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Is there such a thing as a Class K PV wire? Can any 10 AWG single conductor wire be used as PV wire?

AlaskanNoob

Solar Enthusiast
Joined
Feb 20, 2021
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The PV wire we have purchased and see online is 10 AWG 7 strand, or 19 strand wire. But Victron requires Class K PV wire to go into its MPPT RS units.

I have found Class K 10 AWG wire (tinned copper) -- would I be okay slapping some MC4 connectors on it and using it as my PV wire?

Wire specs:

Single Conductor Wire
10 AWG Orange

Legend:

E196955
UL Recognized
AWM 10 AWG OIL RESISTANT 600V VW-1 ARCTIC ULTRAFLEX BLUE® -55°C TO 105°C CSA 234608 TEW 105°C 600V FT1

Rated for and proven in extreme temperatures of -55°C to 105°C

This highly flexible wire combines finely stranded tinned copper with a jacket that resists the abuses of oil, gasoline, sunlight, saltwater, acids, and chemicals. ARCTIC ULTRAFLEX BLUE®has high abrasion resistance and can be used in most 600V applications. UL Listed as AWM (Appliance Wiring Material). Numerous applications including those approved under NEC article 400 and associated articles.

Features:

  • Superior flexibility to -55°C (-67°F)
  • Class K fine stranded tinned copper construction
  • Resists oil, grease, chemicals, abrasion
  • Sunlight and weather resistant
  • Flame retardant (VW-1)
  • UL Recognized and CSA Approved
  • Environmentally safe
  • Made in the USA
Applications:

  • UL 508A Industrial control panels
  • Internal appliance and equipment wiring
  • Inverter cables and wiring
  • Industrial machines and robotics
  • Construction equipment
  • Marine, RV and automotive wiring
  • Medium and heavy-duty trucks and trailers
  • Load banks, motor leads, welding cable
  • Forklifts and golf carts
  • Batteries and chargers
  • Power hookup cable
Manufactured exclusively
by Polar Wire Products

ULR CSA RoHS USA


temperature-icon.jpg
-55°C to 105°C


Construction Specifications:

  • 10 AWG
  • Class K Tinned Copper Stranding (105/30)
  • .120" Conductor Outside Diameter
  • .030" Insulation Thickness
  • .180" Finished Outside Diameter
  • Ampacity at 30°C (86°F)*: 60
  • Ampacity at 40°C (104°F)*: 56
    *Ampacities of 600V and 1000V 105°C AWM wires in air. Ampacities based on single conductor in free air, 30°C or 40°C ambient temperature as specified, 105°C conductor temperature, per NEC table 310-17 (adjusted for 105°C). Free air ratings assume a one-cable-diameter space between adjacent conductors.
 
This article suggests PV wire is different from regular wire. Hmmm.

Yes, solar cable is different than normal cable. Solar cable, also known as Photovoltaic, or PV, cable, is specifically designed to be used with solar energy systems. It is made of a specialized type of coated copper that is resistant to extreme weather and the corrosive effects of ultraviolet radiation.

Solar cable is also tested to meet stringent safety, environmental and temperature requirements. This type of cable is thicker and more rigid than regular electrical cable, allowing lower resistance across the line and enabling greater power transmission.

Solar cable is also designed to withstand a higher voltage, as systems require higher voltage in order to generate a sufficient amount of power. Additionally, solar cables are also UL listed and approved for outdoor Solar applications.
 
The reason why they want you to use a very flexible (high strand count) cable is because the Victron charge controllers that I've seen (I haven't seen the MPPT RS yet) uses a clamping mechanism that compresses the fine strands together and firmly secures the cable to the charge controller connector. This also has benefit of having a lot of contact area. With a low strand count cable you can't compress the thick strands enough to firmly secure the cable plus it will not have good contact area potentially causing excess heating.
 
The reason why they want you to use a very flexible (high strand count) cable is because the Victron charge controllers that I've seen (I haven't seen the MPPT RS yet) uses a clamping mechanism to that compresses the fine strands together and firmly secures the cable to the charge controller connector. This also has benefit of having a lot of contact area. With a low strand count cable you can't compress the thick strands enough to firmly secure the cable plus it will not have good contact area potentially causing excess heating.

Sounds like a good way to do it. I'm just wondering what PV cable people are using that complies with that? I can't find any. I've found 10 AWG wire that meets the specs, but it's not labeled as PV wire so I'm not sure if I can use it or not. Plus it's tinned copper so I don't know if I can use that either (I suspect I can).
 
Sounds like a good way to do it. I'm just wondering what PV cable people are using that complies with that? I can't find any. I've found 10 AWG wire that meets the specs, but it's not labeled as PV wire so I'm not sure if I can use it or not. Plus it's tinned copper so I don't know if I can use that either (I suspect I can).
This stuff?

 
Someone mentioned using 7 strand PV wire from the panel and then into the house, and then connect it to a circuit breaker or master cutoff switch, and from the switch use finer stranded wire rated for the amps and voltage from the circuit breaker / master off to the MPPT.
 
Someone mentioned using 7 strand PV wire from the panel and then into the house, and then connect it to a circuit breaker or master cutoff switch, and from the switch use finer stranded wire rated for the amps and voltage from the circuit breaker / master off to the MPPT.
I was just typing out this exact suggestion.
 
Someone mentioned using 7 strand PV wire from the panel and then into the house, and then connect it to a circuit breaker or master cutoff switch, and from the switch use finer stranded wire rated for the amps and voltage from the circuit breaker / master off to the MPPT.

That sounds like a vote for no such PV wire existing which is odd since Victron apparently thinks people should be wiring solar arrays with the stuff. I wish they'd share where this unicorn wire lives.
 
I believe the main difference between THHN wire and "PV" wire is the UV resistance covering. Beyond that, there are different ratings based on the number of strands. I bought mine from the link below. In 10 awg they carry wire rated for 2000v and 600v, which are 19 strand and 10 strand, respectively. I went with the 2000v rated wire.

www.photovoltaiccable.com
 
wire.png
So the wire in the OP that is tinned copper is not UL 4703 compliant. So technically it's not PV wire. I don't know if it would have worked or not, somebody on the Victron forum said it didn't but didn't specify why not.

But I think I finally found some UL 4703 PV wire that does meet Victron's requirement (the strands are 29 AWG):

 
You have to transition to a different cable type. You don't connect PV wire directly to an MPPT RS. That is a high voltage controller made for stationary installations. Some of their other charge controllers have MC4 connectors directly on the controller so you don't have to transition. They even show in one of their schematics there is a breaker/isolator between the PV array and the MPPT RS: https://www.victronenergy.com/uploa...lBMS-SmartSolar-MPPT-RS-Cerbo-GX-touch-50.pdf.
 
Someone mentioned using 7 strand PV wire from the panel and then into the house, and then connect it to a circuit breaker or master cutoff switch, and from the switch use finer stranded wire rated for the amps and voltage from the circuit breaker / master off to the MPPT.

Now that I've found the AWG 10 PV wire that comports with Victron's requirements, I'm going to cut short sections of it and crimp on some MC4 connectors. Then connect those to the 130' 7-strand PV wire runs out to the solar panel. Then the multi-strand wire will be plugged into the MPPT.

Now I just need to figure out which MC4 connectors are rated for having this multi strand wire plugged into it, and then make sure that will connect with the MC4 connector that will have the 7 strand wire in it.
 
You have to transition to a different cable type. You don't connect PV wire directly to an MPPT RS. That is a high voltage controller made for stationary installations. Some of their other charge controllers have MC4 connectors directly on the controller so you don't have to transition. They even show in one of their schematics there is a breaker/isolator between the PV array and the MPPT RS: https://www.victronenergy.com/uploa...lBMS-SmartSolar-MPPT-RS-Cerbo-GX-touch-50.pdf.
MPPT.png

Can you elaborate on how you don't connect PV wire directly to an MPPT RS?

I'm planning on stripping one end of the newly found PV wires (this 10 AWG PV wire with 84 strands) and inserting them directly into the MPPT as shown in the manual.

That 84-strand PV wire will transition to hundreds of feet of 7-strand PV wire that go to the panels if that's what you're mentioning. Planning on making that transition using some MC4 connectors.

Of course now I'm digging through the guts of what wires go with what kinds of MC4 connectors because certain MC4 connectors work with the 84 strand PV wire, but not the 7 strand and vice versa, and I'll have to figure out how to make it all connect.
 
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If you use this: https://www.solar-electric.com/imo-si32-pel64r-4-true-dc-solar-isolator.html you'd get your isolator and way to transition to a fine strand cable. You also then get ability to disconnect PV array power near the MPPT RS so it would be safe to work on if need be. Run whatever cable you want from the PV array to that isolator and then use fine strand cable from the isolator to the MPPT RS. I'm not clear what kind of connection is in that IMO isolator so you made need to use a ferrule on the fine strand cables to connect them.
 
If you use this: https://www.solar-electric.com/imo-si32-pel64r-4-true-dc-solar-isolator.html you'd get your isolator and way to transition to a fine strand cable. You also then get ability to disconnect PV array power near the MPPT RS so it would be safe to work on if need be. Run whatever cable you want from the PV array to that isolator and then use fine strand cable from the isolator to the MPPT RS. I'm not clear what kind of connection is in that IMO isolator so you made need to use a ferrule on the fine strand cables to connect them.

Thanks, I'll take a look.
 
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